The documents taken at the Abbottabad compound, according to American officials, show that Bin Laden was in touch regularly with the terror network he created. With his whereabouts and activities a mystery in recent years, many intelligence analysts and terrorism experts had concluded that he had been relegated to an inspirational figure with little role in current and future Qaeda operations . .

“He wasn’t just a figurehead,” said one American official, speaking on the condition of anonymity, who had been briefed on the documents. “He continued to plot and plan, to come up with ideas about targets and to communicate those ideas to other senior Qaeda leaders.”

A new bulletin issued tonight by the FBI and the Department of Homeland Security and obtained by ABC News describes the terror organization’s chilling desire to derail a train.

“As of February 2010, al-Qa’ida was allegedly contemplating conducting an operation against trains at an unspecified location in the United States on the 10th anniversary of September 11, 2001,” the document reads, using an alternate spelling for bin Laden’s terror group. “As one option, al-Qa’ida was looking into trying to tip a train by tampering with the rails so that the train would fall off the track at either a valley or a bridge.”

“You can’t guard hundreds of miles of track,” said ABC News consultant and former White House counterterrorism advisor Richard Clarke. “And if they can get to one location that is not well guarded and put explosives on it or do something to cause the train to derail that’s a lot easier than going after an aircraft.”